Material feeding mechanism in sewing machines



Jan. 22, 1963 G. GUSTIN ETAL 3,074,366

MATERIAL FEEDING MECHANISM IN SEWING MACHINES Filed June 24, 1960 5 Sheets-Sheet 1 Fig.1 Fig.2

In uen tors G/z/z /,4/V0 608 TM 4/1 70/v/0 Mam By J MQ 05% A Horney Jan. 22, 1963 G. GUSTlN ETAL 3,074,366

MATERIAL FEEDING MECHANISM IN SEWING MACHINES Filed June 24, 1960 5 Sheets-Sheet 2 Fig. 3

A g 1 4\\\\\\\" 15 1 9 s Inventors Attorney Jan. 22, 1963 e. GUSTIN ETAL 3,074,366

MATERIAL FEEDING MECHANISM IN SEWING MACHINES Filed June 24, 1960 5 Sheets-Sheet 3 Inventors Attorney Jan. 22, 1963 s. GUSTIN ETAI. 3,074,366

MATERIAL FEEDING MECHANISM IN SEWING MACHINES Filed June 24, 1960 5 Sheets-Sheet 4 6 Fug 7 v Fi 8 Fig.9

Inventors Attorney Jan. 22, 1963 e. GUSTIN ETAL MATERJ IAL FEEDING MECHANISM IN SEWING MACHINES 5 Sheets-Sheet 5 Filed June 24, 1960 Fig.1o

m w 2 m m6 AM od WM/ fi ld iihh Patented Jan. 22,, 1963 The mechanism for the feeding of the material in known sewing machines comprises a flamboyant cam which operates on the two parallel internal faces of the forked end of an oscillating member.

The preparation of the profile of said cam and its coupling to the oscillating member require extremely accurate machining.

In addition to this, the cam profile must fulfill the requirement that, for every angular position, it must be included between two parallel tangents with a strictly constant distance between each other. It cannot therefore fulfill simultaneously the different operational requirements. Compromise solutions have therefore been used up to now, giving up some operational requirements in order to achieve other purely mechanical advantages.

The feeding mechanism of the present invention eliminates this drawback entirely by allowing the use of a cam profiled in strict accordance with the operational requirements. In spite of this it is of simple and economical manufactuer and it is not subject, as it occurs at present, to operational irregularities, with the consequent development of undesirable noises in the long run.

This mechanism is characterized in that the cam with the required profile is made to act on a single surface of the oscillating member which is kept in contact with the cam by spring means; during the material feeding operation, the action of the cam overcomes the action of the spring means which, when the material is not being moved, draw the oscillating member back.

The invention will now be described in detail with reference to the enclosed drawings only by way of nonlimitative example. In the drawings:

FIGS. 1 and 2 give a side and front view, respectively, of an embodiment of the mechanism according to the invention;

FIGS. 3 and 4 are similar views of another embodiment of the same mechanism;

F168. 5 and 6 are again similar views of a third embodiment;

FIGS. 7, 8 and 9 are the acceleration, speed and displacement diagrams, respectively, of the oscillating member of the mechanism according to the invention; and

FIGS. 10 to 13 show a device for disconnecting the feeding mechanism, the first in partial elevation and the others in partial plan view and in different positions, respectively.

The corresponding parts in the various figures are indicated with the same reference numbers. The upper transmission shaft 1 of the machine has a cam 2 keyed to it according to the known methods for the control of the material feeding. According to the invention, said cam is made to act on the surface 3 of an oscillating lever 4 (FIGS. 1, 2) or of an oscillating connecting rod 5 (FIGS. 3 to 6). Reciprocal contact is ensured by the spring 6.

In the embodiment illustrated in H68. 1 and 2, the lever 4 is firmly fixed to a beam 7 and to an oscillating shaft 8 and it is further connected wtih the end of the connecting rod 9 by means of the pin bush iii thereof whose position on the beam 7 can be adjusted by means of the roller 11 which slides in the slotted plate 11b is connected to the connecting rod itself, the roller 11 being operated according to a known method by the control lever 12. As is known, according to the position in which the end of the connecting rod 9 is placed along the beam 7, oscillating movements with varying amplitude and eventually reversed direction are imparted to the connecting rod 9 itself according as to whether the end of the connecting rod is on one side or on the other of the center of the oscillating shaft 3 of the lever 4.

Due to the mechanism according to the present invention, the advance of the material always occurs as a result of the positive action of the cam 2 on the contact surface 3 in any position of the end of the connecting rod 9, against the action of the spring 6 which controls the connecting rod 9 only during the idle return stroke. The spring 6 needs therefore be designed only in relation to the inertia forces of the mechanical system.

In the embodiment described in FIGS. 3 and 4, the oscillating connecting rod 5 is acted upon by the spring 6 connected to the control lever 14. This lever is pivoted, with the pivot 15, on the machine frame 16 and is connected by means of the pivot 17 to a small rod 18, in turn connected by the pivot 19 to the connecting rod 5. The oscillations imparted to the rod 5 are transformed according to a known method, into a reciprocating axial movement of the small rod 1%, which, through the pivot 29 and the rod 21, imparts an oscillating movement to the feeding shaft 22, which varies, with regard to amplitude and direction, according to the position of the lever 14.

It is evident in this case too, that it is the positive action of the cam 2 on the surface 3 which causes the advance of the material, while the return stroke of the rod 5 occurs under the action of the spring 6.

In order to reduce to the minimum the load of the spring 6, the latter is connected at one end to the end 23 of the adjustment lever 14- so that it maintains a practically perpendicular position in relation to the axis of the small rod 18 in spite of the displacements of the lever M.

The embodiment indicated in FIGS. 5 and 6 is very similar to that of FIGS. 3 and 4, the difference being that the small rod 18 is replaced by a block 24 which slides in guides 25 of the adjustment lever 14. In order that the action of the spring 6 be made as effective as possible, the spring 6 is arranged so as to lie along a direction practically parallel to the sliding direction of the block 24.

In all the embodiments described above, the movement of the cam 2 determines accelerations of the oscillating member which give rise to forces which tend to cause the said member to approach or move apart from the cam. If we consider as positive the accelerations which cause a pressure of the surface 3 against the cam 2 and negative those which cause their moving apart, We have first of all a positive acceleration during the stage when the surface 3 moves apart from the cam 2 and then a negative one. During the immediately following stage, during which the surface 3 approaches the shaft 1 there is a negative acceleration followed by a positive one. On the other hand, due to the functional requirements of the machine, there must be a dwell period at the beginning and at the end of each moving-apart stage.

It is evident that Whereas the positive accelerations have practically no effect on the operation, the negative accelerations can cause the surface 3 to move apart from the cam 2 when they overcome the action of the spring 6. The negative acceleration in relation to the positive acceleration must therefore be reduced to a minimum when the cam profile is established.

0n the other hand, both in the moving apart and in the approach stages, it is necessary for the accelerationdisplacement diagrams (FIG. 7) to have a positive acceleration area 26 equal to the corresponding negative acceleration area 27 so that the initial and final speed will be zero.

Assuming that a constant positive acceleration and another constant negative acceleration be chosen (minimum maximum value) and assuming that a negative acceleration28 be accepted equal to half the positive acceleration 29, the inversion of the speed must therefore Occur at one third of the angular rotation moving apart or approaching the c am.

The speed diagram (FIG. 8) therefore becomes a triangle 3Q with the apex 31 displaced to a point one third along the base 32. The displacement diagram (FIG. 9*) will be represented by the line 33. It is evident from FIGS. 7 8 and 9 that it is better to choose a cam, designed according to the diagram 33 (FIG. 9) in that it corresponds to negative accelerations which are decidedly smaller and therefore lead to loading of the spring which is lower than those corresponding to the equal acceleration 26 and 27.

The mechanism illustrated in FIGS. to 13 serves to disconnect the feeding action when particular operations must be carried out on the machine such as darning, embroidery, sewing of buttons, preparation of but ton-holes and the like. This is attained in known sewing machines by preventing the fabric pusher from protruding out of the needle plate by excluding the lifting of the fabric pusher. All the mechanical parts for the feeding remain however in operation and it is not usually possible to disconnect the internal parts of the machine which obtain their motion from the main shaft of the machine.

According to the present invention, on the contrary, the disconnecting of the feeding action is effected by keeping the surface 3 of the oscillating member apart from the cam 2 cooperatingtherewith so that the whole of the feeding mechanism stops.

According to the embodiment of FIGS. 10 to 13 which refers to a machine incorporating the feeding mechanism illustrated in FIGS. 1 and 2, this is attained by means of an external handle 41; which moving along the direction of the arrow 1 (FIG. 11) acts on a spring 42 fixed to a point 43 of said handle and to a lower extension 44 of the rod 45. Said extension 44 transmits its displacement to the rod 45 which carries a hook 46 at its upper end. This hook engages with a pin 47 carried by the oscillating lever 4. The latter is thus kept away from the cam 2 whichcauses its normal oscillating motion.

The control rod 45 is guided and supported at the two ends by the fixed guides 51 and 52.

The engagement of the oscillating lever takes place as follows:

From the dwell position (FIG. 11) in which the hook 46 is completely disengaged and the oscillating lever is free, the position illustrated in FIG. 12 is attained with the handle 41 In this position the spring 42 is tensioned and the hook 4-6 is brought near the pin 47, by the tension ofspring 42. A

Under these conditions, engagement is not, as a rule, attained immediately since the hooking-on plane 46' is not necessarily opposite the pin 47. The hook 46, however, is kept against the pin 47 by the action of the spring 42.

Duringthe. subsequent operation of the machine, how ever, the'pin 47 does at one point attain the position of engagement with the hook 46 as a result of the rotation of the cam 2. At this instant, the spring 42 (FIG. 13) pushes the hook -46 andcauses the plane 4 6 to slide on the pin 47 which, is further pulled in the direction of moving the lever 4 apart from. the cam 2, thus latching the love; itself.

The disengagement of the system occurs when the handle 41. is brought again to its dwell position thus disengaging the hook 46 from the pin 47 and freeing the eve sheddar- It; i s eyidentthatembodiments other than thoseherein described can be adapted for the mechanism of the material feeding without departing from the scope of the present invention.

What we claim is:

1. Material feeding mechanism in sewing machines of the type described comprising a flamboyant cam acting on the surface of an oscillating member which transmits reciprocating motion to a material feeder, said cam acting on only one surface of said oscillating member maintained in contact with said cam by spring means, and latch means mounted adjacent said oscillating memher for automatically latching said oscillating member in the position of greatest tension of said spring means and for keeping said surface out of contact with said cam and disconnecting the entire feeding. mechanism to stop transmitting reciprocating motion. to said. material feeder.

2. Mechanism according to claim. 1 in. which said spring means is placed between an oscillating lever operated by the cam and a fixed point on the frame of the machine.

3. Mechanism according to claim 1 in which said spring means is mounted between a small rod carrying the oscillating pin of a connecting rod operated by the cam and the end of a lever which adjusts. the position of saidsmall rod.

4. Mechanism according to claim. 1 in which said spring means is mounted betweenv a point of an oscillating connecting rod operated by the cam and one end of a iever for adjusting the position of slide guides of a block carrying the oscillating pivot of said connecting rod.

5. Mechanism as infclaim 1 wherein said latch means consists of a pinmounted on said oscillating member, a hook lever adapted to engage said pin for keeping said oscillating member in an idle position, and a handle act ing. on said hook lever through further spring means to set said hook lever in position for latching said oscillating member, said handle acting directly on said hook lever for disengaging same from said pin setting said oscillating member free to engage said cam.

6. Material feeding mechanism in, sewing machines of the type described comprising a transmission shaft having a cam keyed thereon mounted in said machine, an oscillating member for transmitting reciprocating move.-v ment to a material feeder having one end adapted, for engaging said cam and the other end being pivotally mounted to, said machine, spring means mounted adjacent said one end of said oscillating member for biasing said one end of said oscillating member against said cam, adjustment means connected to said oscillating member to varyjthe; amplitude thereof while in engagement with said cam, and latching means mounted in said machine adjacent, said oscillating member for automatically latching said oscillating. member when said, spring means is in greatest tension for maintaining said oscillating memher out of contact with said cam and disconnecting the entire feeding mechanism to, stop transmit ing I p r eating movement to said material feeder.

7. Material feeding mechanism according to claim 6 wherein said. adjusting means, consists. of an oscillating shaft mounted on said oscillating member and, extending parallel to said transmission shaft, a beam mounted on said oscillating member and extending perpendicular to said oscillating shaft, a connecting rodv having a bush mounted in one end, for engaging said beam and the other end pivotally mounted to said machine, a plate having one end connected to said one end of said connecting rod containing said hush while the other end has a siot disposed therein, a roller mounted in said slot, and a control lever mounted to said roller to efiect adjustment of said bush along said beam, said spring means being mounted between said machine andsaid one end of said oscillatingmember.

8.; Material feeding mechanism according to claim 6 wherein said adjusting means consists of a small rod having one end pivotally connected adjacent to said one end of said oscillating member, a control lever having one:

end pivotally connected to the other end of said small rod, an intermediate portion pivotally connected to said machine and the other end extending through an aperture of said machine, said spring means being mounted between said one end of said small rod and the other end of said control lever.

9. Material feeding mechanism according to claim 6 wherein said adjusting means consists of a block pivotally connected adjacent to said one end of said oscillating member, a control lever having guides disposed in one end to engage said block, an intermediate portion pivotally connected to said machine and the other end extending through an aperture in said machine, said spring means being mounted between adjacent said one end of said oscillating member and the other end of said control lever.

10. Material feeding mechanism according to claim 6 wherein said latching means consists of a pin mounted on said oscillating member, a hook lever having one end pivotally mounted adjacent said pin and being adapted to engage said pin for keeping said oscillating member in an idle position, a handle mounted in said machine adjacent the other end of said hook lever, and further spring means mounted between said handle and said other end of said hook lever to set said hook lever in position for engaging said pin to latch said oscillating member, said handle acting directly on the other end of said hook lever for disengaging same from said pin setting said oscillating member free to engage said cam.

References Cited in the file of this patent UNITED STATES PATENTS 248,530 Thomas Oct. 18, 1881 304,424 Fuller Sept. 2, 1884 696,039 Grothe Mar. 25, 1902 1,477,264 Hleb Dec. 11, 1923 2,877,726 Gegauf Mar. 17, 1959 2,931,329 Johnson Apr. 5, 1960 

1. MATERIAL FEEDING MECHANISM IN SEWING MACHINES OF THE TYPE DESCRIBED COMPRISING A FLAMBOYANT CAM ACTING ON THE SURFACE OF AN OSCILLATING MEMBER WHICH TRANSMITS RECIPROCATING MOTION TO A MATERIAL FEEDER, SAID CAM ACTING ON ONLY ONE SURFACE OF SAID OSCILLATING MEMBER MAINTAINED IN CONTACT WITH SAID CAM BY SPRING MEANS, AND LATCH MEANS MOUNTED ADJACENT SAID OSCILLATING MEMBER FOR AUTOMATICALLY LATCHING SAID OSCILLATING MEMBER IN THE POSITION OF GREATEST TENSION OF SAID SPRING MEANS AND FOR KEEPING SAID SURFACE OUT OF CONTACT WITH SAID CAM 